Problem: What do the following two equations represent? $-4x+4y = 3$ $-16x-16y = -5$
Putting the first equation in $y = mx + b$ form gives: $-4x+4y = 3$ $4y = 4x+3$ $y = 1x + \dfrac{3}{4}$ Putting the second equation in $y = mx + b$ form gives: $-16x-16y = -5$ $-16y = 16x-5$ $y = -1x + \dfrac{5}{16}$ The slopes are negative inverses of each other, so the lines are perpendicular.